Rotary serial printer for data processing machines



ATTOR NEY Pateted Nov.- 24, 1970 n' i I n l snaai for 4 Fig. 7

gli.

Patented Nov. 24, V1970 3,542,182-

Sheet 2 0! 4 Fig.

HELMUT LANGENBERGER /N VEN TOR.

ATTOR EY Patent@ Nov..24, 1910v 3,542,182

sheet V3' ora 30aY HELMUT LANGENBERQER Patented, Nov.l 1970 3,542,182

"Sheet i of 4 E/l nl Ill I l M35 l vHELMUT LANGENBERGER /NVENTORJ MAcHrNEsf The present invention relates to a yhigh-speed printernfor I data processing'machines,.more particularly; to arotary serial printer forI printing charactersin response to electrical impulses asthe outputofan. electronicdata processing'machine.

Electronic'dat'a processinginstallations operate at extremely high speedsgbut canhe used advantageously only when the input of data to such aninstallation and the output of the ealculated data occur. at equally high Speeds. For ready utilzation, it `is preferable Vthat l the `output of data processing machines bein printed form. Accordingly, many different forms ofhigh-spee'd printershave'been devised 4to record the output 4data atfspeedsjsubstantially equal to theoutput of the data from the` electronic machines.r Most of such printers are `of the parallel. typejwhichareinaturally suitable for recording larger quantities of'data perunit time since theoutput data is printedlasaline of characters'at a time. Theparallel printers take s everald'ifferent formsy one of which employs a continuously rotating-type cylinder.which-:operates on the on the fly principleandrmayhave af' maximumoutput of printed lines totaling 25,l33"charac ters persecond which corresponds with storage space necessaryfor holding sufficient type to print an entire lineflfhere. are "also considerable differences in the durations lof the vimpulses for'disengaging thefprinting magnets from a'lineof print. This difficulty frequently results in an uneven `and irregular positioning ofthe printedv characters. further disadvantage `of parallel-printers utilizing a continuously rotating cylinderis that considerable difficulties are en- It is a further object of the present invention to provide a high-speed printer fordataprocessing machines which overcountered in` guiding andrnoving the .paper being printed.

Usually'a ratchet drive is employed with the ratchet teeth engaging spaced perforations along .the edges of the paper. This results in difficulties in the printing of duplicatesand renders4 it almost impossible to print account'cardsthat require inserts.

In addition tothe foregoing difficulties such parallel printers havethe well known but undesirable characteristic of producing an excessive amountlofrnoiseduring printing. This printing noise is caused by the positioningof the paper between the rotating cylinder-and theprinting hammers so that during each r printing-operation the paper must `be moved at a high rate of accelerationagainst the typecylinder. The difficulty of feedt ing the 'printing inlf to high-speed parallel printers is another undesirable'characteristic In'order to overcome' the disadvantages ofparallel printers as described above yit Vwas )proposed .to utilize a serial'printer which essentially comprises a stationary typing roller in combination withfamoving'highspeed serial printer. Such a construction has Vthe advantages'of thel typewriter having a stationary carriage "and amovableball` head printer.` Such typewritersy have'already been used as output units with data processing installatiprnslfsuchga printer has the advantages of the stationarycarriage typewriter such as facilitating the use of cardinsertslandtlhe use `of` continuous recording paper.

With a stationary typewritercarriage and a laterally movable printer, the time lapsefinthe printer moving from one printing position-td the nextcan be considerably shortened so asto resultin a KVsignifieant"increase in printingjspeed if the mass of the printer is appreciably less than the mass of the typewriter carriage. This is particularly true for extended typewriter'carriages.

`Itis therefore the principalobject of the present invention l to provide a' novel and'irnproved high-speed serial printer for data' processing machines. h

It is'anotherobjectof the present invention to provide a high-speed printer fordata processing machines which is analogous to the vuse of a typewriter having a stationary carriage and laterally movablel printer.

V relatively small mass and having a coordinated printing mechanism which shifts the drum to successive printing positions. This construction considerably increases the output of printed characters per unit time above that of previous systems. In addition, decreasing of the size and simplifying the structure of such a printer reduces the costs of-manufacture land .extends its utility to even smaller installations without sacrificing the previously known high-speed advantages of parallel printers.

In one aspect of the present invention there may be provided a rotatable type drum with its axis of rotationvbeing perpendicular to the printing surface. The drum carries a plurality of type barsarranged circularly adjacent the drum periphery with the-bars being parallel tothe drum axis and movable toward the printingv surface. Mounted in radially extending slots on the drum is a corresponding plurality of hammers which are engageable withrespective type bars. The hammers are movably mounted on the drum and when actuated from theiroperative positions will move the respective type bars into printingpositions. A selector electromagnet is energized to move predetermined hammers into their operative positions. Asecond rotatable shaft is disposed perpendicularly to the rotational axis of the drum and carries an impact wheel having a plurality of .impact teeth. The peripheral path of the impactteethis such-that aharnmer in the operative position is impacted by a tooth so that the impacted hammer and its respective type bar are accelerated toward the lprinting surface at` greatly increased speed. Because of the concurrent rotationof the drum and impact wheel the direction of relative movement of the impacted hammeris toward the printing surface and away from the peripheral path of the impact wheel. As a result of this angular relative movement the next succeeding impact tooth in the peripheral path will clear the impacted hammer.

One or more selector electromagnets may be provided. Where a plurality of selector electromagnets are employed each magnet will engagecertainones ofthe hammers.

The rotating drum and impact wheel are drivingly interconnected by either a'tooth-belt arrangement or by gears.

Other objects and advantages of the present invention will be. apparent upon reference to the accompanying descriptionv when taken in conjunction with the following drawings FIG. l is a perspective view partially in section of the major components of the printer of the present invention with the elements-.being shown in .their normall or nonprinting positions;

FIG. 2 is a horizontal sectional view of a type hammer and the impact wheel teeth illustrated inFIG. 1 and showing schematically the movements of the hammer a'nd teeth during im pacting; FIG. 3 is a perspective view in enlarged scale of a portion of the type drum of FIG. l and showing the outer end construction of the hammers when a plurality of selector electromaglnets are used;

FIG. 4 is a vertical sectional view through a portion of the type drum of FIG. 1 and illustrating the relationship of the selector electromagnetfand the type hammers;

FIG. 5 is a perspective view of the printer driving mechanism comprising a toothed belt;

FIG. 6 is a side elevational view of a portion of a modified printer driving mechanism using gears; and

FIG. 7 is a top plan view of the modified driving mechanism of FIG. 6.

Proceeding next to the drawings wherein line reference symbols indicate the same parts throughout the various views a specific embodiment of the present invention will be described in detail.

As may be seen in FIG. 1 the serial printer of the present invention comprises a symmetrical type drum 1 which is fixedly mounted upon a rotatable shaft 3 so that the drum rotates in the direction indicated by the arrow 1a. The shaft 3 is positioned on an axis which is perpendicular to the printing surface which will be the paper passing over a printing roller 6.

Adjacent the periphery of type drum l there is annularly arranged a series of printing type bars 2 which are parallel to drum shaft 3 and are movable toward and away from the printing surface. The type drum body 4 is provided with a corresponding pluralityof leaf springs 5 whose outer ends are connected to the type bars so as to maintain the type bars in their normal or nonprinting positions as shown in FIG. 1. The printing type characters carried on the ends of type bars 2 rotate continuously at a constant speed in a circular path that is always tangential to the axis of rotation of the printing roller 6. Thus the actual printing operation takes place in region 7 as shown in FIG. 1.

The type drum 1 is also provided with a plurality of radially extending slots 9 in which are received printing hammers 8 corresponding in plurality to type bars 2. Each of the printing hammers is provided with a slot l1 through which passes a circular shaft 10 so that the hammers are capable of pivotal movement and a limited degree of radial movement as defined by the length of slot 11. Theprinting hammers are maintained in their inoperative positions by extensions 12 from printing bars 2 engaging sloping surfaces 13 on the inner faces of the printing hammers. Because of the continuous rotation of type drum l, centrifugal force also will assist in maintaining the hammers in their inoperative positions as shown in FIG. l.

There is provided an impact wheel 14 which is conventional in construction and mounted on shaft 15 which is positioned at right angles to drum shaft 3. The impact wheel shaft 15 is spaced sufficiently above drum shaft 3 so that the impact wheel 14 will clear the drum shaft. The type drum shaft 3 and the impact wheel shaft 15 are drivingly interconnected by means of a toothed belt or gearing both of which are known in the art and will be subsequently described. The periphery of the impact wheel 14 is provided with a number ofimpact teeth 16 positioned to cooperate with the inner ends 13 of that printing hammer which is immediately or almost in front of the printing zone 7 and which has'be'en previously moved into its operative position.

The type drum 1 and the impact wheel 14 can be considered as elements of a single gear train driven by shaft 15 from a continuously running synchronous or nonsynchronous motor in a known manner. The r.p.m. of the impact wheel 14 will have the same ratio to the r.p.m. of the type drum 1 as the number of printing type bars 2 has to the number of impact teeth 16. By way of example, with 50 type bars on the drum and 25 impact teeth on impact wheel I4 the impact wheel would be geared to rotate at twice the speed of drum 1.

The periphery of the circular path of the printing hammers 8 is so positioned with respect to the point of tangency with the periphery of impact teeth 16 that a printing hammer can always be struck by an impact tooth at the same predetermined point. However, contact between the hammer and impact tooth will occur only after a hammer has been moved radially inwardly to its operative position. Thus according to the relationship of the present invention one impact tooth 16 will necessarily impact upon a printing hammer 8 after the hammer has been moved into its operative position.

The printing hammers 8 are shifted into their operative positions by a selector electromagnet 18 mounted a fixed position and outwardly of the drum l as illustrated in FIGS. 1 and 4. The electromagnet 18 which is energized in a manner to be presently described comprises a core 25 which attracts an armature 24 mounted on leaf spring 23 pivoted at one end at 22. The leaf spring 23 is provided on its other end with a striking head 21 which is engageable with the shoulder 17 of a printing hammer in the manner illustrated in FIGS. 1 and 4. The leaf spring 23 is illustrated in FIG. 4 in its normal or nonenergized position. Upon being energized the leaf spring will be attracted to the dotted line position 19. However, the resiliency of the spring will cause striking head 21 to strike shoulder 17 of a predetermined printing hammer. Immediately after striking, the resiliency of the leaf spring will bring the striking head 21 back to its dotted line position where it is spaced from the printing hammers by a distance indicated at 26. Thus, striking head 2l is maintained out of the path of the circularly moving hammers even when the leaf spring is in the energized position. When the electromagnet 18 is deenergized, the leaf spring will return to the position as shown in FIG. 4.

The printing hammerv described herein will operate in a satisfactory manner with one selector electromagnet for thel type drum. However, as an additional precaution against any accidental collision between a striking head 21 and a next successive hammer shoulder 17, two or more electromagnets may be used. In FIG. 3 there is illustrated an arrangement whereby three electromagnets are employed with the striking heads 21 having different axial positions with reference to the type drum so that each striking head coacts only with particular printing hammers. The printing hammers are provided with shoulders 17, 17 and 17" which also have different axial positions with respect to the type drum. In this manner, the striking head 21 of electromagnet A will strike only those printing hammers having stepped shoulder 17 as illustrated in FIG. 3. Similarly, the electromagnets B and C will only strike the respective stepped shoulders 17' and 17".

When using two or more selector electromagnets 18, each electromagnet will thus actuate only a fraction of the total number of printing hammers. For example, the characters on the type bars may be divided into a plurality of groups so that all the printing hammers in a single group are actuated by a particular electromagnet. As a further example of the manner in which a plurality of electromagnets can be employed is for each electromagnet to actuate only a fraction of the total number of type lbars'which make up a combination of individual characters. One of the electromagnets can be assigned to all characters which will occur in the first digital position while another electromagnet can be assigned to those characters which will not occur in the first digital position. It will be apparent that using a number of electromagnets increases the safeguard against accidental striking of the hammers in proportion to the number of electromagnets employed. ln FIG. 5 there is illustrated a driving mechanism for the motor driven drum shaft'3 and the impact wheel shaft 15. This particular driving arrangement is known in the art but is particularly advantageous for use in the present invention. There is provided a toothed belt 28 which passes over a gear 29 fixedly mounted on drum shaft 3. The belt then passes over an idler gear 30a loosely mounted on an intermediate shaft 38, over a gear 31 fixedly mounted on impact wheel shaft 15, down over an idler gear 33 loosely mounted on a shaft 39 which is positioned in vertically elongated openings-34 to facilitate mounting of the belt and to disconnect the driving arrangement. The belt 28 then passes upwardly over a second gear 32 fixedly mounted on shaft l5, downwardly over a second idler gear 30b and then back to gear 29. The direction of movement of particular segments of the belt and'the directions of rotation of the various gears are indicated by the respective arrows on FIG. 5.

ln FIGS. 6 and 7 there is illustrated a modification of the driving arrangement of FIG. 5 wherein directly connected gears are employed. In the modified driving arrangement an intermediate shaft 35 is provided which is drivingly connected to drum shaft 3 through meshing helical gears 36 having their teeth at a 45 angles with respect to the shaft 3. The intermediate shaft 35 is then drivingly connected to impact wheel shaft 15 by meshing spur gears 37.

f between s suc ssiyeprintinugs a-nuinber-of functions must occur in 4[addv r'ifto providing 'sufficiently long time periods betweenm ve' l t of "the individual'scomponents for safety ypurposes Such functions include the" energization of the selecttor ele'ctroirragiets,displacingthe'printing hammer from its `inoperative to its"operativepositiom and moving theprinting Al hamrnerand its respectiveftypebar forwardly into the-printing .'position. 'D'uringthisipreparatjoryphase therefwill also occur eoutpl't'fof af data' processinginstallation, the4 riiiter' Between vmations can be. kept` the moving 'of theiprinte'r from one printing'position to the will n'ot'be nec i lnext so",that?additional'time forV the movement of the printer saryf Ofthe'total 'of 50 printingharnme'rs car- `fried by the` type y:drirm theftinie-thatwill be required for two e'rsjt'o passaiselec'tor electromagnet when the ata'spee'd `of'2,400 r.p.m. will be: 4/ (40 X 50) v The rotation of `thevprinting'type' bars 2 and the printing liammersup'onlhetype drum'is `s'ynchronized'with the asprinting fs'ociatedielectronictstorage unit by means of `a `known photoelecitricio iiductiveiinput d eviceflnforderV to shift a predetermined'printing hammerinto its operative position,

` electromagnetlS iseriergized with a phase shift that'is .I determinedbyfthe speed of rotation of the hammer'and printling bar. Immediately upon the predetermined printing hammer reaching the suitablev positionwith respect to the striking 'head 2 1;v an 'impact will be'y delivered bythe striking head to vthe",liarnriier 'at thatihstant to move thelprinting hammer 'radially inwardly to its operative position. Y

s Thepintinglham'mei:which has now been moved into the operative position willnow move its inner conical end portion lf3'` into thepath `of onfof'theimpact teeth 16. This collision between thefhaiirmerfin the operative position and one of the impactte'eth willpivotthe hammer and itsresp'ectivetype bar toward the printing surface.- The impact wheel I4 together with thetype lcaribe considered as an infinitely large mass andsan"individual impact itooth can be considered as a resilient oscillator. po'nfimpact of atooth with a hammer a portionofithimpactfenergy of the tooth will `initially be returned to theitoothjin'theform of :recoil energy. During the subsequent'resilientforward'movement of the tooth this recoil ehergyfis returnedtothehammer and the'priritingbar. In acs cordancewitli' the Vlawsof mechanics; the forward speed of the hammer. and i tual contact'ofthe impact toothwith the hammer continues printing type bar'are thereby doubled if the acdtiring halfof oscillation periodln effect, thev forward speed i fofftlie ha'mrrie'r and typebar"will`be'acceleratedto almost twice me rotation-a1" speed' of the impact tooth. The impact,

V which is againphase shifted withrespect to time becauseof the resiliency of the impact tooth, will be transmitted by the typebar to arrive at the printing zone 7 `at exactly the right time forimpinging upon thefprinting roll`6. The direction of ,relative movement of the type bar and theprinting hammer withsrespee't 'to eachother toward the printing surface 6 is determined by the velocity of the impacted hammer and the rotational speed ofthe type drum". The printing hammer will be accelerated by the impact of the impact tooth to suchl a velocity thatth hammmer will be moved out of the peripheral path of theinipact wheel along a relative path determined by the relative speeds of the drum and hammer. l

The relative movements of the impacted hammer and the impact tooth are schematically illustrated'in FIG. 2. FIG. 2 illustrates the relationship at the time when impact tooth 16 impacts a printing hammer 8 which has .moved into the impact region 16. The positions of the hammer immediately before and after impact are shown in dotted lines and the positions of impact teeth 16 and 16" immediately before the impact are similarly shown in dotted lines` The direction of movement of the impact teeth through their peripheral path and also the ldirection of rotation of the impact wheel are indicated by the arrow I. Thetdirection of rotation of the type drum and the'path of the printing'ha'rnmer are indicated by the arrow Il. The'resultant of these two directions at right angles to each other is indicated by the arrow III which is the relative path of the printing hammer 8 immediately after impact. It can be seen that because of this relative path the hammer will emerge from the peripheral path of the impact wheel teethand will be cleared by successive impact teeth. y

It isl pointed o ut that the forward speed of the type bar and hammer toward the printing surface after impact is diminished by the'lleaf spring 5 which has one end attached to the drum body 4 and the 'other end connected to the type bar. Further, this leaf spring will guide the type bar and hammer back to their original positions. A plurality of leaf springs may be comv bined into a segment 5'. Under the action of the leafspring or leaf spring segment the hammerin its normal position will lie against the abutment ring 20 as may be seen in FIG. 4.

As pointed out aboveone revolution of the type drum will occur in 25 ms. The preparatory phase of the cycle will occupy 20 ms. It is therefore apparent that the minimum lapse of time between the printing of two characters is similarly equal to 20 ms. if4 the next character to be printed is next in line to the character that has just been printed. On the other hand,if the next character which is to be printed is furthest away from lthe character which has just been printed thenl the maximum I lapse time for a cycle will be 20 plus 25 or 45 ms. The average time between the printing of two characters will therefor be one half of 45 ms. or 22.5 ms. which corresponds to an average printing speed of 30.8 characters per second.

In order to further facilitate the comprehension of the operation of the present invention a complete printing cycle will be described. The type drum l rotates at a speed of 2,400 r.p.m. By means of an inductive or photoelectric input device the electronic storage unit isnotified of the passage of the characters in a phased interval corresponding to the impulse time of the selector electromagnet 18. When the phase position of a type character on the drum coincides with the same character in the storage unit the selector electromagnet will be energized to cause the striking head 21 to hit the correspondin'g printing hammer into its operative position. The hammer in -its operative position then approaches the impact region where it simpacted by one of the impact teeth 16 on the im pact wheel. At the time of impact both the hammer and its associated type bar will be accelerated toward the printing surface. The actual printing impact will then occur with the'type face of the type bar being in vertical position. As described above the hammer 8 will clear the range ofthe impact wheel teeth so as to prevent any further striking of the hammer.

the leaf spring, the type bar and the hammer will be returned to their initial positions. The hammer is still in its operative position but is almost immediately cammed radially outwardly to its inoperative position by a stationary cam 27 positioned immediately behind the printing zone and illustrated in FIG. I.

Thus it can be seen that the present invention has disclosed a high-speed vserial printer which is somewhat analogous to a fixed carriage typewriter. The structure of the printer is relatively simple and has a relatively small mass so as to be capable of high-speed operation and thereby significantly increase the output above that of known printers. Further, the simplified yet high-strength construction of the printer according to the present invention not only constitutes a significant advance in the art of output printers for data processing systems but keeps to a minimum the wear and tear of the moving parts.

It will be understood that this invention is subject to modification in order to adapt it to different uses and conditions and, accordingly, it is desired to comprehend such modification within this invention as may fall within the scope of the appended claims.

lclaim:

l. A high-speed rotary serial printer for data processing machines having a printing surface and comprising a rotatable shaft disposed perpendicularly to the printing surface, a drum mounted on said shaft for rotation therewith, a plurality of type bars on said drum with said type bars being parallel to said drum shaft and moveable axially toward the printing surface, a corresponding plurality of hammers moveably mounted on said drum, means for selectively moving the hammers from inoperative positions into operative positions wherein the hammers are engageable with respective type bars to move axially the selected type bars into printing position when the respective hammers are actuated after being moved to their operative positions, a second rotatable shaft disposed perpendicularly to said first shaft, a continuously rotating impact wheel having a plurality of impact teeth thereon mounted on said second shaft, the peripheral path of said impact wheel teeth being such that a hammer in the operative position is impacted by a tooth so that the impacted hammer and its respective type bar are accelerated toward rthe printing surface at a speed considerably greater than the peripheral speed of the impacting tooth, the velocity of said impacted hammer toward the printing surface and away-from the path of the impact wheel being such that the next succeeding impact tooth in said peripheral path will clear the impacted hammer.

2. A high-speed rotary serial printer as claimed in claim 1 with said type bars being arranged circularly on said drum adjacent the periphery thereof, a circular supporting shaft on said drum, said printing hammers each having a slot therein with said circular supporting shaft passing through said hammer slots to support said hammers for pivotal and limited movement radially on said drum, the inner end of each hammer having a sloping surface thereon directed toward the drum with said sloping surface being engageable with the end of its respective type bar prior to being moved to its operative position, and a corresponding plurality of leaf springs connected to said type bars to retain'said type.bars in their inoperative positions.

3. A high-speed rotary serial printer as claimed in claim 2 with said drum having a plurality of radial slots corresponding to the plurality of said hammers with said hammers being positioncd in said slots, and a stationary abutment ring on said drum passing through said radial slots and engaged by said hammers under the urging of the leaf springs against the hammer sloping surfaces when in the inoperative positions.

4. A high-speed rotary serial printer as claimed in claim 1 with said hammermoving means comprising a stationary selector electromagnet adjacent the periphery of said drum and selectively energizable with respect to a predetermined hammer, a leaf spring having one end pivotally mounted and carrying armature means responsive to said electromagnet when energized, and means on the other end of said leaf spring for striking the inner end of the selected hammer to move said hammer to its operative position, said leaf spring having such resiliency that the striking means will hit a hammer upon energization of the electromagnet and after striking the striking means will return to its energized position spaced from the hammer and out of the path of the circularly moving hammers.

5. A high-speed rotary serial printer as claimed in claim 4 with there beinga plurality of said selector electromagnets and the respective striking means having various positions with respect to said hammer inner endssaid hammer inner ends having differently positioned stepped shoulders thereon corresponding to the plurality of said electromagnets so that each electromagnet will move only those hammers having corresgaondin ly positioned stepped shoulders.

. A hig -speed rotary serial printer as claimed in claim 5 with said type bars being divided into a plurality of groups of printing symbols corresponding to the plurality of said selector electromagnets so that each selector electromagnet controls only those type bars in a particular group and their respective hammers. 

